The present invention relates to integrated circuits, and more specifically, to electrical connections in multilayer integrated circuits.
Integrated circuits often include interconnect layers that include lines of conductive material such as copper, aluminum, tungsten, silver, or alloys that include copper and tungsten. Integrated circuits also often include multiple layers that are electrically connected using vertical connections called vias.
The interconnect layers may be connected to devices on the integrated circuit by the vias. The vias are often etched through layers of the integrated circuit and filled with a conductive material. It is desirable to form vias having a high aspect ratio and low resistance.